Hi, I use a slightly different way, I put:
GRUB_GFXMODE="1440x900 640x480"
in /etc/defaults/grub (native resolution first, fall-back one isn't
necessary, it's the default).
Then in /etc/grub.d/00_header I add gfxpayload=keep to this section
(around line 80):
[...]
if loadfont `make_system_path_relative_to_its_root ${GRUB_FONT_PATH}` ; then
set gfxmode=${GRUB_GFXMODE}
set gfxpayload=keep <<<<<<< here it is
insmod gfxterm
insmod ${GRUB_VIDEO_BACKEND}
if terminal_output gfxterm ; then true ; else
[...]
It's working for me on Debian Squeeze and Ubuntu, but needs to be
updated if 00_header is overwritten during update (not often). It's just
a workaround until gfxpayload= is picked up in /etc/default/grub.
My 2 cents.